1. Field of the Invention
The present invention relates to an adjustable positioning device for a head of a sewing machine, allowing easy insertion and removal of thick materials during a sewing operation.
2. Description of the Related Art
A typical sewing machine includes a needle, a presser foot fixed below the needle, and a needle seat below the presser foot. A material to be sewed is inserted into a space between the presser foot and the needle seat and removed after sewing. In a case of a sewing operation of multiple layers of cloth or leather or of a thick material having a total thickness greater than the space between the presser foot and the needle seat, the needle and the presser foot are detached before insertion of the material and then reassembled for sewing operation, and the same detaching and reassembling procedures are required for removal of the thick material, resulting in troublesome operation. Furthermore, in another case that the material has to be rolled in the space, the rolled and sewed material can only be removed in a forward/backward direction, not allowing removal in a lateral direction, leading to inconvenience and difficulties to operation.